Enteral and parenteral energy intake and neurodevelopment in preterm infants: a systematic review

Objectives We performed a systematic review of all the available evidence to study the effect of enteral and parenteral energy intakes in preterm infants on neurodevelopment (NDV) and cerebral growth evaluated by NDV scales, magnetic resonance imaging (MRI) and head circumference (HC). Data source MEDLINE, Scopus and ISI Web of Knowledge databases, using the following medical subject headings and terms: premature infants, nutrition, brain, nervous system/growth and development. Manual search of the reference lists of all eligible articles. Study selection Studies in which the intervention applied was different energy intakes in parenteral nutrition (PN) and/or enteral nutrition (EN) in the first weeks of life, investigating NDV. Data extraction Data regarding nutrition and NDV were collected and analysed. Results Thirty-five studies were included: 12 randomised controlled trials (RCTs) and 23 cohort studies. 8 RCT and 15 cohort studies investigated NDV by using NDV scales. Of those, 2 RTCs and 5 Cohort studies found not significant difference in NDV evaluated by Bayley scale, between neonates fed by high caloric nutrition and those who received lower energy intakes in early life. One RCT and 2 cohort studies observed a positive effect of EN on NDV. Conversely, in one cohort study negative correlation between parenteral energy intake and NDV was described. By the analysis of the data from RCTs and cohort studies, greater HC in the groups receiving aggressive PN and total enhanced nutrition, respectively, was observed. However, 2 RCTs and 1 Cohort study do not report any differences in terms of HC. Inconclusive results were reported by studies that investigated cerebral growth by MRI. The studies observing a positive effect of enhanced nutrition on cerebral and basal ganglia growth, caudate nucleus, cerebellum and thalami volume investigated only the influence of EN. Conclusion: The impact of the energy intake in early life on NDV remains still undefined. Positive impact on brain development encourages the administration of recommended energy intake mainly by EN and suggests a more wary approach of enhanced nutritional strategies by parenteral route. Further studies are advocated to elucidate the optimal nutritional intervention for preterms in order to improve NDV.